What are wildcards and why are they useful?
Wildcards are a way to match any combination of words or symbols. The best way to explain wildcards is to show a few examples. Consider the following:
|email@example.com||Block mail from joe at somewhere.com|
|firstname.lastname@example.org||Block mail from anyone who's username starts with a J atsomewhere.com|
|*@somewhere.com||Block mail from anyone at somewhere.com|
|*savetrees*||Block mail from anyone at a domain name that has the wordsavetrees in it.|
|*.gov||Block mail from anyone at a government address|
|205.199.212.*||Block mail from anyone at the network of 205.199.212.x|
|*||VERY DANGEROUS. This would block all electronic mail from everyone.|
Wildcards can be used anywhere inside email addresses, domain names or IP addresses. Wildcards can only be used at the beginning or end of subject, message content or header matches.